package com.jia.jianzhiOffer;
/**
 * 面试题26：树的子结构
 * 题目描述
输入两棵二叉树A，B，判断B是不是A的子结构。（ps：我们约定空树不是任意一个树的子结构）
 * @author Administrator
 *
 */
public class Pro26 {
    public boolean HasSubtree(TreeNode root1,TreeNode root2) {
        if(root1 == null || root2 == null)
            return false;
        return isSubtreeWithRoot(root1, root2)
            ||HasSubtree(root1.left, root2)
            ||HasSubtree(root1.right, root2);
    }
    private boolean isSubtreeWithRoot(TreeNode root1, TreeNode root2) {
        if(root2 == null)
            return true;
        if(root1 == null)
            return false;
        if(root1.val != root2.val)
            return false;
        return isSubtreeWithRoot(root1.left, root2.left) && isSubtreeWithRoot(root1.right, root2.right);
    }
}
